Problem: Khan.scratchpad.disable(); To move up to the maestro level in his piano school, Daniel needs to master at least $178$ songs. Daniel has already mastered $23$ songs. If Daniel can master $9$ songs per month, what is the minimum number of months it will take him to move to the maestro level?
To solve this, let's set up an expression to show how many songs Daniel will have mastered after each month. Number of songs mastered $=$ $ $ Months at school $\times$ Songs mastered per month $+$ Songs already mastered Since Daniel Needs to have at least $178$ songs mastered to move to maestro level, we can set up an inequality to find the number of months needed. Number of songs mastered $\geq 178$ Months at school $\times$ Songs mastered per month $ +$ Songs already mastered $\geq 178$ We are solving for the months spent at school, so let the number of months be represented by the variable $x$ We can now plug in: $x \cdot 9 + 23 \geq 178$ $ x \cdot 9 \geq 178 - 23 $ $ x \cdot 9 \geq 155 $ $x \geq \dfrac{155}{9} \approx 17.22$ Since we only care about whole months that Daniel has spent working, we round $17.22$ up to $18$ Daniel must work for at least 18 months.